Week 9 immunity & inflammation

Question 1

2 divisions of immunity

Answer 1

1. Innate immunity

2. Adaptive immunity

Question 2

3 Levels of innate immunity

Answer 2

1. Defence barrier
2. Cellular - phagocytes and NK cells
3. Humoral - soluble factors

Question 3

3 Types of soluble factors

Answer 3

1. Acute phase protein
2. Complements
3. Interferons

Question 4

3 Functions of complements

Answer 4

1. Cytolysis
2. Chemotaxis - attract phagocytes
3. Opsonization

Question 5

4 steps of phagocytosis

Answer 5

1. Chemotaxis
2. Adherence
3. Ingestion
4. Digestion

Question 6

Receptors that neutrophils and macrophages are equipped with

Answer 6

Pattern Recognition receptors (PRRs):

for recognition of pathogens

Question 7

Functions of neutrophils and macrophages

Answer 7

Neutrophils

1. Phagocytosis
2. Production of anti-microbial proteins
3. Secretion of inflammatory cytokines

Macrophages:

1. Phagocytosis
2. Production of free radicals: toxic to bacteria and intracellular parasites
3. Secretion of pro-inflammatory cytokines

Question 8

Main Function of Natural Killer Cells

Substance present inside NK cell

Answer 8

1. Kill cancer cells or virus-infected cells
2. Secrete cytokines

Contains
Cytotoxic granules with perforins (pore-forming protein) and granzymes (promote apoptosis)

Question 9

Receptors possessed by NK cells

Answer 9

1. Killer activating receptor (KAR)

2. Killer inhibitory receptor (KIR)

Question 10

4 Effector Functions of complement proteins

Answer 10

1. Opsonization
2. Chemotaxis
3. Cytolysis: attack membrane
4. Inflammation

Question 11

Definition of cytokines

An important type of cytokine in immune function

Answer 11

Proteins made by cells that can module behaviour/function/differentiation of other cells

Important type:
interferons

Question 12

Functions of interferons

Answer 12

1. Suppress viral replication in infected cells -> limit viral spread
2. Activate other immune cells -> enhance viral clearance

Question 13

2 Arms of adaptive immunity

Answer 13

1. Humoral immunity

2. Cell-mediated immunity

Question 14

What are primary and secondary lymphoid organs?

Give an example of each

Answer 14

Primary lymphoid organs:
for development and maturation of lymphocytes
(e.g. thymus, bone marrow)

Secondary lymphoid organs:
for differentiation of lymphocytes
(e.g. spleen, lymph nodes)

Question 15

What are immunoglobin and its basic structure?

Answer 15

Antibodies

Basic structure:
2 light chains and 2 heavy chains
-> Variable region (Fab)
-> Constant region (Fc)

Question 16

Major effector functions of B cells

Answer 16

1. Production of antigen-specific antibodies

2. Production of cytokines

Question 17

Functions of T cells
which class of MHC molecules does it recognize?

Answer 17

CD8+ (cytotoxic T cell):
recognize peptide on MHC class I on antigen-presenting cell
mediate cytotoxic killing of antigen-specific target cell

CD4+ (helper T cell):
recognize peptide on MHC class II
produce cytokines -> modulate functions of other immune cells

Question 18

3 Phases of adaptive immunity

Answer 18

1. Recognition
2. Activation
3. Reaction

Question 19

4 General Functions of B cells

Answer 19

1. Neutraliziation
2. Opsonization
3. Complement activation
4. Antibody-dependent cellular cytotoxicity

Question 20

5 signs of inflammation

Answer 20

1. Redness
2. Swelling
3. Pain
4. Loss of function
5. Heat

Question 21

3 Outcomes of acute inflammation

Answer 21

1. Resolution
2. Healing by scar
3. Progression into chronic inflammation

Question 22

4 Characteristics of adaptive immunity

Answer 22

1. Antigen specific
2. Diverse repertoire
3. Immunological memory
4. Self and non-self discrimination

Question 23

3 Major differences between primary and secondary responses

Answer 23

1. Time of induction
2. Magnitude of reaction
3. Decline in reaction after reaction phase

Question 24

2 levels of self and non-self discrimination

Answer 24

1. Central tolerance:
   deletion of self-reactive T/B cells in primary lymphoid organ
2. Peripheral tolerance:
   deletion(apoptosis)/inactivation (anergy)/suppression of self-reactive T/B cells in secondary lymphoid organs

Question 25

Components involved in acute inflammation

Answer 25

1. Tissue damage 2. Chemical mediators 3. Blood vessels 4. Neutrophils

Question 26

2 Categories of chemical mediators released during acute inflammation

Answer 26

1. Cell-derived mediators (e.g. histamine from mast cell) | 2. Plasma protein-derived mediators (e.g. complement system)

Question 27

How do vasodilation and increased vascular permeability help in inflammation?

Answer 27

Vasodilation: Facilitates migration of neutrophils out of blood vessels by moving them to peripheral zone (margination) as vessel is packed with slow-moving RBC Increased vascular permeability: 1. Immunoglobins move to damaged tissues 2. Coagulation proteins move into tissue for blood clot formation

Question 28

How do neutrophils reach injury site?

Answer 28

``` 1. Leave blood vessel adhesion molecules (selectin and integrin) stick leukocytes to endothelial cells -> emigration ``` 2. Move to site of injury by chemotaxis Neutrophils recognize concentration gradient of chemoattractants -> move by amoeboid movement

Question 29

What are chemokines?

Answer 29

small proteins that can cause migration of cells

Question 30

4 Common causes of acute inflammation

Answer 30

1. Physical agent - burn 2. Biological agent - bacteria, fungi 3. Chemical agents 4. Hypersensitivity

Question 31

4 Functions of monocytes (macrophages)

Answer 31

1. Phagocytosis 2. Antigen presentation 3. Secretion of mediators 4. Induction of general effects

Question 32

What are antigens

Answer 32

Cellular structures that induce immune responses

Question 33

Composition of fungal cell membrane

Answer 33

Ergosterol

Question 34

3 classifications of fungus

Answer 34

1. Yeast - unicellular 2. Mould - multicellular 3. Dimorphic fungi - yeast at 37oC mould at 25oC

Question 35

4 Histological hallmarks of chronic inflammation

Answer 35

1. Infiltration of mononuclear inflammatory cells 2. Granulation tissue 3. Tissue destruction and fibrosis 4. Regeneration

Question 36

What is granulomatous inflammation?

Answer 36

A special type of chronic inflammation Characterized by formation of granuloma - collection of modified macrophages called 'epitheloid cells'